1. Field of the Invention
This invention relates to electrical connectors and more particularly to coaxial cable connectors.
2. Description of Related Art
The increasing demand for miniaturization and the decreased tolerances resulting from the requirements of modern data processing and communications equipment have greatly increased the cost of assembling electrical connectors used in such systems.
Due to the use of solid state components in computers and general information processing equipment, and therefore the need for low power level signals, man made noise interference has become a more serious problem than was the case when higher power levels were used in electronic equipment. Consequently, electronic devices require more shielding to preserve signal-to-noise ratios. In addition, because of the increasingly wider bandwidths and faster computation speeds of signal processing devices, the use of efficient coaxial cables capable of Megahertz performance has become increasingly necessary.
The coaxial cables used in high frequency communications and signal processing systems generally consist of a center conductor, an outer conductor circumferentially disposed around the center conductor, a cylindrical dielectric occupying the space between the center and the outer conductors, and an outer cylindrical jacket surrounding the outer conductor to provide electrical and environmental insulation. The outer conductor is usually woven out of fine metallic threads in the form of braid although, in a few specific cases, the outer conductor may be a solid metallic tube. Other common shielded cables include twin axial and triaxial cables, each of which generally utilizes a braided shield-type outer conductor.
FIG. 1 shows a shielded cable connector plug which is widely used to connect high frequency information signal carrying conductors. This type of connector is known as an "N"-type connector and includes a unitized body 2 and rear crimp ferrule 5 which is individually sized to the particular cable accommodated. The outer conductor of the coaxial cable is separated from the core dielectric and placed between a rear ferrule portion 3 on the unitized body 2, and crimped between a crimping ferrule 5 and the portion 3. Grooves 4 are provided in portion 3 to ensure good electrical contact and to hold the shield against axial stress.
The unitized body 2 includes a center bore in which is placed a cylindrical dielectric insulator member 6. Dielectric member 6 electrically insulates the outer body member 2 from an inner contact 7, which includes a bore 12 into which the center conductor of the coaxial cable is placed.
The outer conductor of the connector plug is mechanically bonded to the unitized body. Conventionally, this requires an expensively accurate staking operation, as indicated by reference numeral 13. It is essential that the cylindrical contact portion 10 of the outer contact be perfectly aligned with the center axis of inner contact 7, and thus great precision in assembly is required.
In addition to the staking operation, assembly of this type of connector requires provision of a coupling nut 8 and retaining ring 9 for securing the contact to a female jack type connector having external threads. In order to install the coupling nut and retaining ring, special dedicated assembly tooling is required, promoting labor intensive operations.